BATTERY MODULE WITH A STACK OF FLEXIBLE PACKS JOINTLY INTERLOCKED TOGETHER, AND SUPPORTING INTERLOCKED BUSBARDS

Description

Domaine technique

[0001] The present invention relates to the field of electrochemical accumulators, and more particularly to metal-ion accumulators.

[0002] More particularly, the invention relates to a battery module, with a stack of flexible packaging accumulators.

[0003] The invention aims firstly to improve assemblies by stacking flexible accumulators.

[0004] Although described with reference to a Lithium-ion accumulator, the invention applies to any metal-ion electrochemical accumulator, i.e. also Sodium-ion, Magnesium-ion, Aluminum-ion...or more generally to any electrochemical accumulator. The invention applies to any chemistry of metal-ion accumulators, such as for example NMC / Graphite, NCA / Graphite, NMC / G-Si, LFP / Graphite, Na-ion with liquid electrolyte or so-called solid electrolyte.

[0005] A battery module according to the invention may be on-board or stationary. For example, the fields of electric and hybrid transport and grid-connected storage systems may be envisaged within the scope of the invention. Technique antérieure

[0006] As illustrated schematically in figures 1 et 2 , a lithium-ion battery or accumulator usually comprises at least one electrochemical cell C consisting of an electrolyte constituent 1, impregnated in a separator making it possible to electrically insulate the electrodes, between a positive electrode or cathode 2 and a negative electrode or anode 3, a current collector 4 connected to the cathode 2, a current collector 5 connected to the anode 3 and finally, a packaging 6 arranged to contain the electrochemical cell and make it sealed against the outside air and the electrolyte inside the cell, while being crossed by a part of the current collectors 4, 5.

[0007] The architecture of conventional lithium-ion batteries is an architecture that can be described as monopolar, because it has a single electrochemical cell comprising an anode, a cathode and an electrolyte. Several types of monopolar architecture geometry are known: a cylindrical geometry, with winding around a cylindrical axis as disclosed in patent application US 2006 / 0121348, a prismatic geometry, with winding around a parallelepiped axis as disclosed in patents US 7348098, US 7338733; a stacked geometry as disclosed in patent applications US 2008 / 060189, US 2008 / 0057392, and patent US 7335448.

[0008] The electrolyte component may be in solid, liquid or gel form. In the latter form, the component may comprise a polymer or microporous composite separator soaked in organic or ionic liquid electrolyte(s) which allows the movement of the Lithium ion from the cathode to the anode for charging and vice versa for discharging, which generates the current. The electrolyte is generally a mixture of organic solvents, for example carbonates to which a lithium salt, typically LiPF 6 , is added.

[0009] The positive electrode or cathode is made of lithium cation insertion materials which are generally composite, such as lithium iron phosphate LiFePO 4 , lithium cobalt oxide LiCoO 2 , lithium manganese oxide, possibly substituted, LiMn 2 O 4 or transition metal oxide, such as lamellar materials for example, a material based on LiNixMnyCozO 2 with x+y+z = 1, such as LiNi 0.33 Mn 0.33 Co 0.33 O 2 , or a material based on nickel cobalt aluminum oxide type LiNixCoyAlzO2 with x+y+z = 1, such as LiNi 0.8 Co 0.15 Al 0.05 O 2 .

[0010] The negative electrode or anode is very often made of carbon, graphite or Li 4 TiO 5 O 12 (titanate material), possibly perhaps silicon-based or lithium-based, or tin-based and their alloys or silicon-based composite. This negative electrode, like the positive electrode, may also contain electronically conductive additives as well as polymer additives which give it mechanical properties and electrochemical performances appropriate to the lithium-ion battery application or its implementation process.

[0011] The anode and cathode made of lithium insertion material can be continuously deposited using a standard technique in the form of an active layer on a metal sheet or foil constituting a current collector.

[0012] The current collector connected to the positive electrode is usually made of aluminum.

[0013] The current collector connected to the negative electrode is usually made of copper, nickel, nickel-plated copper, or aluminum.

[0014] Specifically, aluminum is used for current collectors common to positive and negative electrodes of titanate Li 4 Ti 5 O 12 . Copper is rather for negative electrodes of graphite (Cgr), silicon (Si) or silicon composite (Si-C).

[0015] Traditionally, a Li-ion battery or accumulator uses a pair of materials at the anode and cathode allowing it to operate at a voltage level, typically between 1.5 and 4.2 Volts.

[0016] Depending on the type of application, the aim is to produce either a thin and flexible lithium-ion battery or a rigid battery: the packaging is then either flexible or rigid and in the latter case constitutes a sort of case.

[0017] Rigid packaging (cases) is usually made from a metallic material, typically an aluminum alloy or stainless steel, or a rigid polymer such as acrylonitrile butadiene styrene (ABS).

[0018] Flexible packaging, commonly referred to as "Pouch", is usually made from a multi-layer composite material consisting of an aluminum foil covered by one or more polymer films laminated by bonding. In most of these flexible packagings, the polymer covering the aluminum is chosen from polyethylene (PE), propylene, polyamide (PA) or can be in the form of an adhesive layer made of polyester-polyurethane. Showa Denko markets this type of composite material for use as battery packaging under the references NADR-0N25 / AL40 / CPP40 or No. ADR-0N25 / AL40 / CPP80.

[0019] There figure 3 illustrates this type of flexible packaging 6 which is arranged to insulate and seal the electrochemical cell C while being crossed by a part of two strips or tabs 4, 5, commonly called in English "tab", forming the terminals or poles and which extend in the plane of the electrochemical cell. The tab 4, constituting the positive terminal, is in the form of a metal strip with a thickness of 0.2 to 0.4 mm, most often made of aluminum. The tab 5, constituting the negative terminal, is in the form of a metal strip of 0.2 to 0.4 mm, most often made of nickel material or copper or nickel-plated copper.

[0020] The main advantage of flexible packaging is its lightness. Li-ion batteries with the highest energy densities therefore have flexible packaging.

[0021] A flexible accumulator, commonly called in English « Thin Film Battery», is most often made up of a single electrochemical cell.

[0022] The total thickness of the battery with its flexible packaging is generally less than 16 mm, which is a function of the dimensions and chemistry of the electrode materials, without affecting the performance during operation of the battery.

[0023] A battery pack is made up of a variable number of accumulators, which can reach several thousand, which are electrically connected in series or in parallel with each other and generally by connection bars, usually called busbars.

[0024] In the development and manufacturing of lithium-ion batteries, each profile / new demand, regardless of the market players, requires precise sizing (series / parallel electrical architectures, mechanical, thermal, etc.) to optimally design a high-performance and safe battery pack.

[0025] In particular, the safety of lithium-ion batteries must be considered at the level of a single battery, a module and a battery pack.

[0026] It is known, in particular to increase energy densities, to produce battery packs by stacking flexible packaging accumulators, the output terminals of the electrodes (tabs) being electrically connected in series or in parallel with each other.

[0027] Furthermore, accumulators must sometimes be put under mechanical compression in order to maximize their lifespan.

[0028] Indeed, it is also known that good control of a compression force applied to electrochemical cells brings a gain in lifespan of the cells and the related battery pack.

[0029] It is also known that there is an optimal compression force for cells to maximize their lifespan. If the compression force is reduced by 50% compared to the optimal compression force, there is generally an increase in aging of the order of 50%.

[0030] In fact, compression applied to the largest active surface of an electrochemical cell limits the delamination of its internal layers (electrodes, separator, active layers) and therefore allows a significant gain in performance in terms of lifespan and nominal operation.

[0031] Depending on the shape of the accumulators, the compression to be applied is more or less important. In the case of prismatic geometry accumulators with flexible packaging, it turns out that compression can be essential.

[0032] In the context of the invention, the term "accumulator of prismatic geometry" means an accumulator of generally prismatic shape, that is to say of generally parallelepiped shape, flattened along one dimension, independently of its embodiment which could be by winding a cell, by stacking, etc.

[0033] Compression is usually applied by means of mechanical tie rods that are arranged around the individual accumulators stacked in groups. The tightening torque applied to the tie rods determines the compressive force applied to the cells.

[0034] A major disadvantage of mechanical tie rods is that it is very difficult to control the compression force during operation of the battery pack accumulators, as well as during their aging. Indeed, during the charging and discharging of the accumulators, and during their aging, they tend to undergo volume variations due to swelling / deflation of the cells.

[0035] This phenomenon of cell swelling increases with aging, which leads to a sharp increase in the compression force to be applied. In fact, this reduces the lifespan of the cells and leads to mechanical and active material oversizing.

[0036] Thus, generally speaking, to compensate for this predictable degradation, manufacturers usually design an oversized battery pack to ensure a specific end-of-life performance. For example, for end-of-life performance of a 10Ah pack, typically after 10 years, designers initially size a 12Ah battery pack. In other words, they allow for a margin of around 20% to compensate for cell aging.

[0037] Another difficulty inherent in an assembly by stacking flexible accumulators is to be able to ensure reliable electrical connections between the electrode terminals (tabs) of the different stacked accumulators without excessively increasing the weight or the complexity of the assembly itself.

[0038] This difficulty is all the greater as the terminals are in the form of flexible tabs, made of a very thin metal strip, typically 0.2 to 0.4 mm.

[0039] Typically, electrode tabs are connected to each other using wires, plates, or busbars by welding. For this reason, the electrode tabs are partially bent, and the plates or busbars are connected to the bent portions of the other electrode tabs by welding, which can be complex.

[0040] Additionally, connected parts may separate from each other due to external impacts, which may lead to an increase in the number of defective products.

[0041] Finally, this welding assembly eliminates any possibility of replacing a defective accumulator with another within the stack, or at an unreasonable cost.

[0042] Several solutions are described in the literature for producing battery modules with flexible packaging stacks of accumulators with electrical connections between their terminals or poles.

[0043] Patent US9023504B1 describes a battery module with spacers arranged individually between two adjacent accumulators, each spacer comprising a base portion in surface contact with the flexible packaging of an accumulator, a wing portion projecting from the base portion to at least partially cover the longitudinal edges of two adjacent accumulators and finally a fixing portion intended to mechanically couple the spacer to an adjacent spacer. Such a module has many disadvantages. First of all, as dimensioned and arranged, each of the spacers only truly protects an accumulator over a portion of its thickness. In addition, given the shape of these spacers, there is no protection of the upper portion or the lower edge of the accumulator. This can be very detrimental, knowing that in general, the flexible packaging of an accumulator is of small thickness, most often less than 0.2 mm.On the other hand, this patent US9023504B1 does not take into consideration the electrical connection to be provided at the level of the tabs (terminals) of the accumulator. Thus, there is neither positioning nor pressure on the tabs which could allow a favorable mode of electrical connection of the accumulators between them to produce an assembly in battery modules.

[0044] Patent EP1834365B1 discloses a battery module with a stack of flexible packaging accumulators, the terminals (tabs) of which are brought into contact and electrically connected to each other by means of bolts passing through them. Such a module also has many disadvantages. First of all, it is necessary to first drill each of the tabs, probably with a minimum of precision, which is not easy given their thickness. In addition, the electrical contact between tabs is proportional to the force provided by the tightening torque of a bolt. This torque must be precisely measured so as not to deform each of the closing plates on the front and rear faces of the module. Finally, the force of compressing the tabs by this tightening of bolts is located mainly in the upper part of the module, i.e. in the area of ​​the electrical connections between tabs.

[0045] Patent CN105226320B describes a stacked battery module in which each accumulator is housed in a support with its terminals (tabs) assembled by welding to pads carried by the support. The disadvantages of such a module are also numerous. When assembling the module, that is to say the different accumulator supports together, it is noted that there is no localized compression at the level of the electrical connections. There is an assembly with compression of the different stages each consisting of a support with its accumulator, by the insertion of long threaded rods through fasteners of each support, each fastener being spaced by a part forming a spacer to maintain a constant thickness after tightening the module. This assembly requires a large number of reference parts, most often metallic, which considerably increase the total mass of the module, and therefore harm the mass density of the module.

[0046] The applicant also proposed in the patent application filed on October 15, 2020 under No. FR2010587, a battery module comprising a plurality of individual supports stacked on top of each other and in each of which is housed a flexible packaging accumulator, with mechanical assembly of the individual supports together by clipping / snap-fastening means positioned on the longitudinal edges of each individual support. This solution is advantageous in many configurations. However, in certain accumulator configurations, the mechanical strength of the clipping / snap-fastening means may not be sufficient or at the cost of oversizing. Also, in certain space-constrained environments, it is important to make at least all the fixing parts between accumulator supports visible because this can present a risk of snagging or even destruction by the other mechanical parts around them.However, the clipping / snap-on means do not meet this possibility.

[0047] There is therefore a need to improve flexible packaging stacked battery modules, particularly to overcome the aforementioned drawbacks.

[0048] The aim of the invention is to meet at least part of this need. Exposé de l'invention

[0049] To this end, the invention relates, in one of its aspects, to a battery module comprising: a plurality of accumulators, in particular of prismatic geometry, each comprising at least one electrochemical cell C formed of a cathode, an anode and an electrolyte interposed between the cathode and the anode, and a flexible packaging arranged to contain the electrochemical cell in a sealed manner while being crossed by a portion of two tabs forming the poles or terminals which extend in the plane of the electrochemical cell; a plurality of blind frames, elongated in a longitudinal and lateral direction, each blind frame forming a support with housing for one of the plurality of accumulators, the supports being stacked and fixed on each other in a stacking direction orthogonal to the directions, each support comprising internally, along one of its longitudinal and / or lateral edges, means of connection by complementarity of shapes with at least one adjacent support;the connecting means being arranged so as not to protrude outside the stack once the connections have been made. a plurality of pairs of metal bars, each pair of bars being inserted into a housing provided in one of the lateral and / or longitudinal edges of one of the supports to form a pair of terminals, a portion of each terminal being in pressure contact against a pole or terminal of one of the accumulators while another portion of each terminal is in pressure contact with an adjacent terminal portion within the stack, the pressure contacts within the stack of supports being obtained by the connections by complementary shapes between adjacent supports. ;

[0050] We recall here that the usual meaning which is that of invention, given to a connection by complementarities of forms: the geometric forms of the parts are complementary and ensure the direct connection between them.

[0051] It is specified that the expression “each support comprising internally” means the blind internal portion of the support.

[0052] The term "pressure contact" means mechanical contact with applied pressure.

[0053] Advantageously, the module is configured so that the longitudinal edges of the module form a flat surface once the connections are made.

[0054] According to an advantageous embodiment, the means of connection by complementarity of shapes comprise, for each support: a plurality of notches distributed at a distance from each other along at least one of the longitudinal edges of one of the main faces of the support; a plurality of notches distributed at a distance from each other along at least one of the longitudinal edges of the other of the main faces of the support, such that relative longitudinal sliding between two adjacent supports causes each notch of a longitudinal edge to engage in a notch of a longitudinal edge, defining a closing position for the two supports.

[0055] According to this mode and an advantageous variant embodiment, the means of connection by complementarity of shapes comprise, for each support: at least one notch arranged on one of the lateral edges of one of the main faces of the support; at least one notch arranged on one of the lateral edges of the other of the main faces of the support, such that during relative longitudinal sliding between two adjacent supports, the notch of a lateral edge of the support engages in a lateral notch in the closed position of the two supports.

[0056] Advantageously, the notches and the crenellations are configured respectively in tenons and mortises so as to constitute dovetail connections.

[0057] Advantageously, the notches and the slots have a T-shaped cross-section. According to an advantageous variant, the other portion of each lug is fitted into the adjacent lug portion within the stack.

[0058] According to this advantageous variant, the other portion of each lug and the adjacent lug portion within the stack being configured respectively in tenon and mortise so as to constitute a dovetail connection.

[0059] Preferably, all the terminals of the same polarity are electrically connected to each other to form a busbar.

[0060] According to another advantageous embodiment variant, each lug and / or each support is (are) configured to absorb the movements induced by the connection by complementary shapes between adjacent supports so as to guarantee contact pressure of the portion of each lug against a pole or terminal of one of the accumulators and thereby guarantee permanent electrical contact between the terminals or poles and the terminal lugs in the stack.

[0061] To ensure this contact pressure, the part of the support opposite and / or the portion of each terminal in contact with a pole or terminal of one of the accumulators advantageously includes one or more bosses.

[0062] Advantageously, all the male or female terminals are identical to each other, and preferably made of aluminum. Offering terminals of the same material, the same surface area and the same shape, provides a common external interface to standardize the electrical connection(s) with busbars for series or parallel connection of the terminals of the supports of the battery module according to the invention.

[0063] Aluminum is a preferred material for module terminals for the following reasons: it has a low density, typically a density of 2.7 g / cm 3< lower than that of copper or nickel, which is 8.9 g / cm 3< . This allows a significant mass saving for each subassembly of the battery module, consisting of a support equipped with two terminals; it has very good electrical conductivity: at a mass equal to copper, aluminum has twice the electrical conductivity. it is easily weldable by a laser welding process. It is thus possible to consider using aluminum busbars which will be welded directly onto the aluminum terminals of the module according to the invention instead of the state-of-the-art copper busbars, which are screwed onto terminal terminals.

[0064] For a Li-ion application, each battery being a Li-ion battery in which: the negative electrode(s) material is chosen from the group comprising graphite, lithium, titanate oxide Li 4 TiO 5 O 12 , silicon, the positive electrode(s) material is chosen from the group comprising LiFePO 4 , LiCoO 2 , LiNi 0.33 Mn 0.33 Co 0.33 O 2 .

[0065] The invention also relates to a battery pack comprising at least two battery modules as described above, electrically connected to each other by means of at least one busbar soldered to at least part of the terminal portions, outside the stack of the module.

[0066] The invention finally relates to a method for producing a battery module as described above, comprising the following steps: i / insertion of each pair of bars forming terminals into the housings of each support, so that it is held by them; ii / housing of each accumulator in one of the plurality of supports with the output terminals of each accumulator facing the pair of terminals; iii / stacking by relative sliding along their longitudinal edges between the adjacent supports until the connections are made by complementary shapes between them.

[0067] Thus, the invention essentially consists of defining a battery module comprising a plurality of individual supports stacked on top of each other and in each of which is housed a flexible packaging accumulator ("pouch"), each support housing metal bars forming terminals which individually make an electrical connection by pressure contact with a terminal (tab) of one of the accumulators.

[0068] In order to obtain this electrical connection by contact, the assembly of the individual supports between them is carried out mechanically by means of connecting means by complementary forms positioned along the longitudinal edges of each individual support, which makes it possible to obtain a robust mechanical connection. Thus, each individual support integrates by definition the function of fixing by clamping to connect to another individual support.

[0069] The closure between two adjacent supports is thus obtained by a single translational movement which allows the complementary shapes to engage with each other.

[0070] Locking means, also in complementary shapes, arranged on the lateral edges of the accumulator supports lock the closure achieved in a way.

[0071] Advantageously, the terminal shapes are designed so that they fit into each other, and their arrangement is designed so that they are brought into contact with the output terminals of the accumulators, simultaneously with the sliding to assemble the supports together. This eliminates the need for any welding to ensure the electrical connections within the same module.

[0072] Ultimately, the invention brings many advantages, including: electrical connections at the accumulator outputs which are obtained by contact with pressure and are therefore not a screwed or welded connection as according to the state of the art with their related disadvantages as follows; a simplification of design of a battery module compared to those according to the state of the art, with a limited number of parts. In particular, there is no need to add fixing parts, such as threaded rods, screws, nuts, clamping plates, etc. the elimination of a welding process step, by electrical means or ultrasonic welding, necessary in the solutions according to the state of the art; the possibility of using a different type of material for the output lug or terminal of each support, compared to that of the accumulator tabs. The resulting advantage is to standardize all the lugs implemented for the battery module.This standardization allows in particular to weld the two aluminum lugs per support to a busbar following the same assembly process. a favorable impact on the mass energy density of a battery module: the mass gain achieved on all the metal fixing parts, usually used in state-of-the-art solutions, will improve the mass energy density (Wh / kg) of a battery; due to the solderless electrical connections between the lugs of each support and the tabs of the accumulator it houses, it becomes easier to recover each accumulator in the case of a step of disassembly of a battery module, for replacement in the event of a defect or for recycling; assembly operations of a battery module which are carried out without any electrical voltage.

[0073] Furthermore, compared to a snap-on / clip-on solution, as described in application FR2010587, the major advantages are as follows: a mechanical assembly which can withstand higher pressures, in particular due to the swelling of accumulators, particularly large ones; complete integration of the connecting means between individual accumulator supports inside them, which makes the surfaces of the longitudinal and lateral edges of the modules flat and avoids any risk of deterioration or even breakage of these connecting means.

[0074] Other advantages and characteristics of the invention will become more apparent upon reading the detailed description of examples of implementation of the invention given by way of illustration and not limitation with reference to the following figures. Brève description des dessins

[0075] [ Fig 1 ] there figure 1 is an exploded perspective schematic view showing the various elements of a lithium-ion battery. Fig 2 ] there figure 2 is a front view showing a prismatic lithium-ion battery with its flexible packaging according to the state of the art. Fig 3 ] there figure 3 is a perspective view of a prismatic lithium-ion battery with its state-of-the-art flexible packaging. Fig 4 ] there figure 4 is a perspective view of part of a battery module according to the invention, before assembly and after assembly between two blind frames forming supports in which accumulators are individually housed. Fig 5 ] there figure 5 is a photographic reproduction showing the stacking and assembly by means of a complementary shape connection of a plurality of supports with the accumulators housed therein for the production of a battery module according to the invention. Fig 5A ] there figure 5A is a detailed sectional view showing an alternative embodiment of a metal strip forming a connection terminal with an accumulator tab, which is intended to be inserted into a battery module support according to the invention. Fig 6 ] there figure 6 is a perspective view showing a main face of a battery module holder according to the invention. Fig 7 ] there figure 7 is a perspective view showing the other main face of a battery module holder according to the invention. Fig 8 ] there figure 8 is a cross-sectional view showing part of the dovetail connection means between two adjacent supports of a battery module according to the invention. Fig 9 ] there figure 9 is a cross-sectional view showing an alternative embodiment of the figure 8 . [ Fig 10 ] there figure 10 is a perspective view showing a metal strip forming a connection terminal according to the variant embodiment of the figure 5A . [ Fig 11 ] there figure 11 is a perspective view showing a metal strip forming a connection terminal complementary to that of the figure 10 . [ Fig 12 ] there figure 12 is a partial perspective view showing the arrangement of an accumulator housed in an individual support of a battery module according to the invention. Fig 13 ] there figure 13 is a perspective view showing an alternative embodiment of an electrical connection between two adjacent supports, before their assembly. Fig 14A ] there figure 14A is a perspective view showing a preliminary assembly step between two supports housing accumulators of a battery module according to the invention. Fig 14B ] there figure 14B is a perspective view showing the preliminary assembly step between two supports housing accumulators of a battery module according to the invention. Fig 14C ] there figure 14C is a perspective view showing the assembly step between two supports housing accumulators of a battery module according to the invention. Fig 14D ] there figure 14D is a perspective view showing the finalized assembly between two supports housing accumulators of a battery module according to the invention. Description détaillée

[0076] THE figures 1 à 3 relate to different examples of Li-ion accumulator, flexible packaging according to the state of the art. These figures 1 à 3 have already been commented on in the preamble and are therefore not commented on further below.

[0077] For the sake of clarity, the same references designating the same elements according to the state of the art and according to the invention are used for all figures 1 to 11D.

[0078] Throughout the present application, the terms "lower", "upper", "bottom", "top", "below" and "above" are to be understood by reference to a battery module according to the invention with Li-ion accumulators positioned horizontally.

[0079] Likewise, the terms "longitudinal" and "lateral" are to be considered in relation to the longitudinal direction X in which an accumulator support according to the invention is elongated.

[0080] In the examples illustrated below, the accumulators A1 to AN+1 illustrated are in prismatic format, with flexible packaging 6, usually called “pouch”.

[0081] Accumulators A1 to AN+1 can be electrically connected in series and / or in parallel in a module according to the invention. The electrical series and / or parallel connection depends on the orientation of the accumulators.

[0082] We have represented in figure 4 , an example of a part of a battery module M according to the invention comprising several adjacent accumulators A1, A2, ..AN, AN+1.

[0083] Each accumulator A1, A2 ..AN, AN+1 is housed in a blind frame 10.1, 10.2, ..10N, 10N+1 elongated in a longitudinal direction (X) and in a lateral direction (Y), which thus forms a support for the accumulator.

[0084] Each of the supports 10.1, 10.2, ..10N, 10N+1 is of general rectangular parallelepiped shape with two lateral edges 11, 13 connected to each other by two longitudinal edges 12, 14 parallel to the longitudinal direction (X).

[0085] The supports 10.1, 10.2, ..10N, 10N+1 are stacked on top of each other, preferably being nested at least partially inside each other, in a stacking direction (Z) orthogonal to the directions (X) and (Y).

[0086] Each of the supports 10.1, 10.2, ..10N, 10N+1 is fixed to the adjacent support(s) by means of connecting by complementary shapes 2, arranged on at least one of the longitudinal edges 12, 14 of each support. These clipping / snap-fastening means 2 make it possible to obtain robust mechanical connections between the different stacked supports.

[0087] More precisely, as shown in figures 6 And 7 , each 10.1 support includes: a plurality of notches 20 distributed at a distance from each other along each of the longitudinal edges 12, 14 of one of the main faces of the support; a plurality of notches 21 distributed at a distance from each other along each of the longitudinal edges 12, 14 of the other of the main faces of the support.

[0088] Preferably, these notches 20 and these crenellations 21 are configured respectively as tenons and mortises so as to constitute dovetail connections.

[0089] The relative arrangement between the notches 20 and slots 21 is made in such a way that a relative longitudinal sliding between two adjacent supports 10.1, 10.2 ..., causes the engagement of each notch 20 in a slot 21 by defining a closing position of the two supports 10.1, 10.2 ...

[0090] In other words, the notches 20 of the lower main face of the accumulator 10.2 from above engage individually by sliding along the longitudinal axis X in the notches 21 of the upper main face of the accumulator 10.1 from below.

[0091] As also shown, the construction and relative arrangement between notches 20 and slots defines a sliding stroke L of limited length relative to the overall length of the accumulators A1, A2, ... and the support frames 10.1, 10.2... This avoids damaging the accumulators and their connections 4, 5 during assembly of the module.

[0092] To block the closure between supports 10.1, 10.2..., additional connecting means 2 are also provided: at least one notch 23 arranged on one of the lateral edges 11, 13 of one of the main faces of the support; at least one notch 24, in the form of a groove, arranged on one of the lateral edges 11, 13 of the other of the main faces of the support.

[0093] The relative arrangement between the notches 23 and grooves 24 is made in such a way that during the relative longitudinal sliding between two adjacent supports 10.1, 10.2, the notch 23 engages in a groove 24 in the closed position of the two supports.

[0094] In other words, concomitantly with the closure on the longitudinal edges 13, 14 between adjacent supports 10.1, 10.2, the blocking of this closure is achieved by the insertion of the notches 23 into the grooves 24.

[0095] Preferably, like the notches 20 and crenellations 21, the notches 23 and grooves 24 are configured respectively as tenons and mortises so as to constitute dovetail connections. For example, a T-shaped section ( figure 8 ) or trapezoid ( figure 9 ) to make these dovetail joints.

[0096] Advantageously, all the connecting means 20 to 24 are arranged so as not to protrude outside the stack once the connections have been made.

[0097] In other words, when the connections by shape complementarities are made, all the longitudinals 13, 14 form the same flat, smooth surface. The same applies to the lateral edges 11, 13.

[0098] Thus, once the M module is assembled, there is no risk of unexpectedly catching or even damaging the connection means 2 because they are not accessible from outside the module.

[0099] Each of the supports 10.1, 10.2, ..10N, 10N+1 forms with the connecting means 2 a single monolithic part made of electrically insulating plastic material. A support can for example be made of polyetherimide (PEI), acrylonitrile butadiene styrene (ABS), polyamide (PA) or polylactic acid (PLA). The preferred production process is 3D printing. 3D printable materials are generally of the type: PLA, ABS, PA12, etc. However, it is entirely possible to produce these parts by machining, and the materials used would be of the type: POM C, Delrin (POM), FR4, PEEK, etc.

[0100] To ensure the electrical connections between the different accumulators A1-AN+1 of the same battery module M, each support 10.1, 10.2, ..10N, 10N+1 comprises a pair of slots 25 in each of which a metal bar 100, 101 is inserted to form a pair of terminals which can also be designated as terminal or output terminals. In the stack of the module M, a portion of each terminal 100 is in pressure contact against a pole or terminal 4, 5 of one of the accumulators A1 to AN+1. Another portion of each terminal 100 is in pressure contact against an adjacent terminal portion. Thus, electrical continuity is ensured between all the accumulators A1 to AN+1. Advantageously, all the terminals 100 or 101 are identical to each other within the same battery module, that is to say of the same dimensions and made of the same material. Preferably, these terminals are made of aluminum.

[0101] According to an advantageous embodiment shown in figures 5A , 10 et 11 , it is planned to produce male and female terminals 100, 101 of complementary shapes and to arrange a pair, for example male, in an upper accumulator support 10.2 and a female pair in the adjacent lower accumulator support 10.1.

[0102] Thus, a female terminal 100 comprises a groove 102 and a portion 104 for contact with a tab 4 or 5 of the accumulator.

[0103] A male terminal 101 comprises a rib 103 of complementary shapes with a groove 102 and also a portion 105 of contact with a tab 4 or 5 of the accumulator.

[0104] The fitting of a male terminal 101 of a support 10.2 into a female terminal 100 of an adjacent support 10.2 is advantageously done simultaneously with the relative sliding between the two supports 10.1, 10.2 to achieve closure between them. Alternatively, the terminals can combine the two male-female characteristics by having on opposite faces of the same terminal the shapes 102 and 103. The face bearing shape 102 can thus cooperate with an adjacent support bearing shape 103, and on the other side the face bearing shape 103 can cooperate with an adjacent support bearing shape 102.

[0105] Thus, by stacking with successive sliding of the different supports 10.1, ...10.n of the same battery module M, connection busbars are formed by successive fitting of the male and female terminals.

[0106] Thus, no welding between terminals 100, 101 of the same polarity is required in a given module M.

[0107] In order to guarantee sufficient mechanical pressure between the contact portions 104, 105 of the terminals 100, 101 with the tabs 4 or 5 of the accumulators housed A1, A2...in the supports 10.1, 10.2...it is advantageous to provide bosses which will apply additional pressure when the supports are closed by sliding.

[0108] As shown schematically in figure 13 , these bosses 106, 110 can be made directly on the contact portions 104, 105 of the terminals 100, 101 and / or directly formed in the part of the support 10.1, 10.2 opposite the portions 104, 105.

[0109] We now recap with reference to the figures 14A à 14D the assembly by complementary shapes between adjacent supports in order to constitute a battery module according to the invention.

[0110] Etape i / : a pair of bars forming terminals 100 or 101 are inserted into the slots 25 of each support 10.1, 10.2 provided for this purpose, so that these terminals 100, 101 are held.

[0111] Etape ii / : we come to house each accumulator A1, A2,... in a given support 10.1, 10.2... by positioning the output terminals (tabs) 4, 5 of each accumulator opposite the pair of terminals 100 or 101 ( figure 14A ).

[0112] Etape iii / : the stacking is then carried out by relative sliding along their longitudinal edges 12, 14 between the adjacent supports 10.1, 10.2... until the connections are made by complementary shapes between them.

[0113] More precisely, we bring a support 10.2 opposite an adjacent support 10.1 ( figures 14A, 14B) then they are made to slide relatively to each other so that the notches 20 engage in the slots 21 according to the predefined translation stroke L. The supports 10.1, 10.2 are thus closed and their longitudinal edges 13 or 14 form a single flat surface.

[0114] At the same time, the notches 23 engage in the grooves 24 and thus block the closure between adjacent supports 10.1, 10.2...

[0115] Simultaneously also, the male terminals 101 fit into the female terminals 100. Inside the supports 10.1, 10.2, the closing by sliding between supports has caused contact with pressure, possibly increased by the bosses 106, 110 provided for this purpose, between the portions 104, 105 of the terminals 100, 101 and the tabs 4, 5 forming the output terminals.

[0116] The invention is not limited to the examples which have just been described.

[0117] Other variations and improvements may be envisaged without departing from the scope of the invention, as defined in the claims.

[0118] If in all of the examples illustrated, the flexible packaging of the accumulators in accordance with the invention is of prismatic format, the invention of course applies to all accumulators with flexible packaging.

[0119] A battery module M according to the invention may comprise a number of stacked accumulators and associated supports, which is determined according to each application.

Claims

1. Battery module (M), comprising: - a plurality of accumulators, in particular of prismatic geometry (A1, A2...AN+1), each comprising at least one electrochemical cell C formed by a cathode (2), an anode (3) and an electrolyte interposed between the cathode and the anode, and a flexible package (6) arranged to contain the electrochemical cell in a sealed manner while having passing through it a portion of two tabs (4, 5) that form the poles or terminals which extend in the plane of the electrochemical cell; - a plurality of blind frames (10.1, 10.2...10.N+1) that are elongate in a longitudinal direction (X) and lateral direction (Y), each blind frame forming a support with housing for one of the plurality of accumulators, the supports being stacked and fixed to one another in a stacking direction (Z) orthogonal to the directions (X,Y), each support internally comprising, along one of its longitudinal edges (12, 14) and / or lateral edges (11, 13), connecting means for interlocking with at least one adjacent support through complementing shapes; the connecting means being arranged so as not to project outside the stack once the interlocking connections have been made; - a plurality of pairs of metal strips (100), each pair of strips being inserted into a housing formed in one of the lateral edges (11, 13) and / or longitudinal edges (12, 14) of one of the supports to form a pair of lugs, one portion (104, 105) of each lug being in pressing contact with a pole or terminal of one of the accumulators while another portion (102) of each lug is in pressing contact with an adjacent lug portion (103) within the stack, the pressing contacts within the stack of supports being obtained by the interlocking connections of adjacent supports through complementing shapes.

2. Battery module (M) according to Claim 1, the module being configured such that the longitudinal edges (12, 14) of the module form a flat surface after the interlocking connections have been made.

3. Battery module (M) according to Claim 1 or 2, the connecting means (20) for interlocking through complementing shapes comprising, for each support: - a plurality of crenellation teeth (20, 23) spaced apart along at least one of the longitudinal edges of one of the main faces of the support; - a plurality of crenellation slots (21, 24) spaced apart along at least one of the longitudinal edges of the other of the main faces of the support, so that longitudinal sliding of two adjacent supports relative to one another causes each crenellation tooth of a longitudinal edge to engage in a crenellation slot of a longitudinal edge, thereby defining a closed position of the two supports.

4. Battery module (M) according to Claim 3, the connecting means (20) for interlocking through complementing shapes comprising, for each support: - at least one crenellation tooth (20, 23) arranged on one of the lateral edges of one of the main faces of the support; - at least one crenellation slot (21, 24) arranged on one of the lateral edges of the other of the main faces of the support, in such a way that, during longitudinal sliding of two adjacent supports relative to one another, the crenellation tooth of a support lateral edge engages in a lateral crenellation slot with the two supports in the closed position.

5. Battery module (M) according to one of Claims 3 and 4, the crenellation teeth and the crenellation slots being configured as tenons and as mortises, respectively, so as to form dovetail connections.

6. Battery module (M) according to Claim 5, the crenellation teeth and the crenellation slots having a T-shaped cross section.

7. Battery module (M) according to one of the preceding claims, the other portion (102) of each lug being nested into the adjacent lug portion (103) within the stack.

8. Battery module (M) according to Claim 7, the other portion (102) of each lug and the adjacent lug portion (103) within the stack being configured as a tenon and as a mortise, respectively, so as to form a dovetail connection.

9. Battery module (M) according to one of the preceding claims, all of the lugs of the same polarity being electrically connected to one another to form a busbar.

10. Battery module (M) according to one of the preceding claims, each lug and / or each support being configured to absorb the displacements induced by the interlocking connection of adjacent supports through complementing shapes so as to guarantee a pressing contact of the portion of each lug against a pole or terminal of one of the accumulators and thereby guarantee permanent electrical contact between the terminals or poles and the terminal lugs in the stack.

11. Battery module (M) according to Claim 10, the part of the support facing and / or the portion of each lug in contact with a pole or terminal of one of the accumulators comprising one or more bosses (106, 110).

12. Battery module (M) according to one of the preceding claims, each accumulator being an Li-ion accumulator in which: - the material of the negative electrode(s) is selected from the group comprising graphite, lithium, the titanate oxide Li4TiO5O12 and silicon; - the material of the positive electrode(s) is selected from the group comprising LiFePO4, LiCoO2 and LiNi0.33Mn0.33Co0.33O2.

13. Battery pack comprising at least two battery modules (M) according to one of the preceding claims electrically connected to one another by means of at least one busbar welded to at least part of the lug portions, outside the stack of the module.

14. Method for manufacturing a battery module (M) according to one of Claims 2 to 12, comprising the following steps: i / inserting each pair of lug-forming strips into the housings of each support so that it is held thereby; ii / housing each accumulator in one of the plurality of supports with the output terminals of each accumulator facing the pair of lugs; iii / stacking the adjacent supports by sliding along their longitudinal edges relative to one another until the interlocking connections through complementing shapes are made.